With the popularization of portable electronic equipment such as a smart-phone and a portable game player, a touch panel which detects an input position in a display screen is used widely. Unlike a trackball, the touch panel equipped with a planate input screen cannot give a user a three-dimensional operational feeling, for example.
On the contrary, a patent document 1 (see Japanese Laid-Open Patent Application No. 2003-296014) discloses a pointing device that has a dome-shaped input screen and detects an input position based on the change of an electric potential by contact of the electrode patterns of two layers in the input screen, and the electrode patterns are arranged so as to form a gap therebetween. A patent document 2 (see Japanese Laid-Open Patent Application No. 2003-91360) discloses a pointing device that has an input screen of a convex curve and detects an input position based on the change of an electric capacity between the electrodes of two layers provided in the input screen.